Phormium are a tall genus of hardy perennials.
They range in height from 90 cm to over 3 metres (3 to 10 feet).
Most Phormium plants grown in gardens are half hardy perennials. They bloom in the summer.
Phormium tenax by Wallygrom.
They are mainly grown for their attractive leaves. These are sword shaped, and striped red, white, or yellow.
Some common names for members of Phormium plant genus include Mountain Flax, Flax Lily, and New Zealand Flax.
Phormium tenax (New Zealand Flax / New Zealand Hemp), photograph by Forest and Kim Starr; CC.
Phormium colensoi (Lesser New Zealand Flax), picture by RuthP; CC.
The seeds of New Zealand flax, Mountain Flax and other Phormium species should be sown outdoors in February. Simply cover the seeds once sown.
Alternatively, they can be started off indoors. Start growing them about 2 to 3 months in advance.
The germination time of Phormium plant seeds varies widely, ranging from one to six months. They should germinate fine at about 15 to 18 degrees centigrade (59 to 64°F).
Phormium plants should be spaced 30 cm (12 inches; small species), 50 cm (20 inches; medium sized species), or 90+ cm apart (over 3 feet; larger varieties).
They are quite versatile plants, and can be grown in both sunny and partially shaded areas.
The soil that Mountain Flax and other Phormium plants grow in should be moist, sandy and have a fertile composition.
It is easy to look after Mountain flax, they require a moist soil so water regularly, and divide every three years or so to maintain vigorous growth.
If you require more Phormium plants, then propagate by division in the springtime.
I hope that you enjoyed this guide on how to grow Phormium plants. You may also enjoy the following Gardener's HQ growing guides: How to grow Aloe-veraMountain Avens, Ixiolirion, and Asphodeline plants.